KR20060037451A - Air suspension system with air shut off valve - Google Patents

Abstract

An air suspension control system (10), primarily for use with a vehicle, which increases ride stability and minimizes air losses to the air suspension control system (10) during normal operation of the vehicle by utilization of an air restriction valve (16) to restrict the air introduced into or exhausted from an air spring (18) in response to a received control signal.

Description

Air suspension system with air shut off valve

The present invention relates to a height control valve in a vehicle suspension, and more particularly to an air limiting valve used in connection with a height adjustment valve or a leveling valve.

Air suspension systems are increasingly used in vehicle suspensions, in the installation of semi-tracker / trailer trucks, and in the seats and cabs of other vehicles. In general, air suspension systems have a height control valve that maintains a specified or selected height of the suspension. For example, in a semi-trailer / trailer truck installation, the specified height is the distance between the vehicle frame and the axle. The air suspension system will detect any change in the specified height and adjust the air pressure in the springs located between the vehicle frame and the axle. In this way, the air suspension system maintains the specified height between the vehicle frame and the axle even under variable load loads.

The height control valve is actuated by selectively supplying air to the air spring, or by venting air therefrom, which is located between the vehicle frame and the trailing arm. A towing arm is provided which holds the axle such that adjusting the air spring correspondingly adjusts the distance between the axle and the vehicle frame. In general, the height control valve is mounted to the vehicle frame, and the height control valve is provided with a control arm connected to the traction arm via a connecting device. In this way, if the distance between the traction arm and the vehicle frame changes, the connecting device will cause the control arm to rotate the control shaft inside the height control valve, which controls the introduction of air into or out of the air spring. . Although mechanical connections are widely used to vary the distance between the axle and the vehicle frame, other measuring transducers such as optical sensors, variable capacitors, variable resistors or any other suitable Transducers can be used effectively.

Typically the height control valve has three air ports, which are an air spring port connected to an air spring, an inlet port connected to a pressurized air source, and an exhaust port open to the atmosphere. In order to reduce the distance from the vehicle frame and the axle, the height control valve opens fluid communication between the air spring port and the exhaust port, whereby pressurized air from the air spring can be exhausted into the atmosphere through the control valve. In order to increase the distance from the vehicle frame and the axle, the height control valve opens fluid communication between the inlet port and the air spring port, whereby pressurized air from the pressurized air source can enter the air spring through the control valve. . When the air spring is at the selected height, the valve is in the neutral position so that the air spring port is isolated from both the inlet port and the exhaust port.

During normal operation of the vehicle, especially during heavy loads, the semi-wrecker / trailer tends to swing back and forth, sideways, forwards or backwards, for example on uneven road surfaces, weather conditions or vehicle orientation. Vibrates due to even changes. These changes in load will again lead to an expansion and contraction of the distance between the axle and the vehicle frame, which will be measured by the air suspension system. The air suspension system is adapted to vary the selected height between the axle and the vehicle frame. The air springs will respond to varying distances between the axle and the vehicle by alternating introduction of air into or out of it. It is not necessary to maintain the selected height in this way while the vehicle is in operation. In fact, this constant periodic movement of the system is very undesired as it significantly shortens the life of the equipment, resulting in expensive maintenance costs and long vehicle downtime while being repaired or being inspected.

For example, when the van tow / trailer approaches the loading dock and the trailer height must be adjusted to match the height of the loading dock, or when the tow truck must be adjusted to connect or disconnect the trailer, the air suspension Changes in the system are commonly used. Moreover, when the trailer is loaded, it is advantageous for the height control valve to automatically adjust the height and level of the trailer. However, once the height is selected based on the load and the level of the trailer is determined, it is not desirable to continuously adjust the height between the vehicle frame and the axle due to small changes in distance. However, sudden changes in load during vehicle operation can cause significant changes in the distance between the axle and the vehicle frame. In this case, it is important for the air suspension system to adjust the air springs to maintain the selected height.

Various systems have been used in an attempt to minimize air consumption during normal operation of the air suspension system. The most common method has attenuated or reduced the dynamic vibration imparted on the valve through a mechanical damper integrated in the valve. Other methods try to profile the flow of air in the valve during normal operation and minimize the flow rate close to the arm motion. All of these methods have proven adequately successful, but have not eliminated the problem.

Alternatively, electronic leveling systems have been used to minimize the consumption of air during normal operation of the air suspension system. For electronic leveling systems, a filter action algorithm is used to conserve air. While this method is relatively effective, the cost of the electronic system is so expensive that its usefulness in the market is limited. While electronic systems are superior to other methods previously listed, electronic systems are much more complex to design, install, repair, and replace, further adding to the cost of the system.

U.S. Patent No. 5,048,867 (867 patent) relates to solving another problem, namely making the operation of a shut-off valve independent of the closing pressure which loads the shut-off valve so that a small volume size can be provided to the valve, The '876 patent discloses a shutoff valve in series with a height control valve. However, the height control valve and the directional control valve are controlled by a control signal based on the height measuring device. (867 patent, ninth column, lines 31 to 53) Thus, the system disclosed and suggested in the 867 patent does not minimize the air loss for the air suspension system during normal operation of the vehicle, which means that between the vehicle frame and the axle This is because both the shutoff valve and the height control valve will respond to the vibration of the vehicle by unnecessarily adding or evacuating air to the air spring based on the variable measurement distance.

Thus, there is a desire for an air suspension system that will minimize air loss in the air suspension system and periodic movement of the equipment while the vehicle is in normal operation.

It is also desirable to provide a system to selectively disconnect the control valve of the air suspension system during normal operation of the vehicle, based on the selected control criteria.

Moreover, it is desirable to provide a system in which various control input criteria such as manual and automatic are provided to selectively operate the height control valve.

It is further desirable to provide a system that will reduce installation, maintenance, and operating costs associated with air suspension systems.

It is also desirable to provide a simple, easy to install and highly reliable air suspension system.

The above and other objects of the present invention are achieved by minimizing air loss in the air suspension system during normal operation. An air limit valve is inserted between the height control valve and the air spring. The air restriction valve releases fluid coupling of the air spring to the height control valve such that during normal operation of the vehicle the height control valve cannot introduce compressed air into or out of the air spring.

The air limit valve is operated by various control inputs that can be derived from any onboard vehicle data monitoring system, for example automatic braking system signals, electronic braking system signals, signals from motion sensors, operator inputs, mounting Or any other signal that may be generated by the vehicle data sensing system, or a combination of the above, but is not limited thereto.

In an advantageous embodiment, the vehicle air suspension control system is provided with a pressurized air source and an air spring. The system has a height control valve having an air inlet port connected to a pressurized air source, an exhaust port connected to the atmosphere, and an air spring port connected to the air spring, the height control valve comprising: an air inlet port and an air spring port, an exhaust port and The air spring port, or the air inlet port, the air spring port, and the exhaust port can be operated to selectively engage between neutral positions isolated from each other. The system further includes an air restriction valve fluidly coupled between the height control valve and the air spring, which can be operated to selectively open and close the fluid communication between the height restriction valve and the air spring. The system also has a first control input based on the first parameter to control the height control valve and a second control input based on the second parameter to control the air restriction valve, the second parameter being different from the first parameter. Do. A system is provided wherein the first parameter is selected to include the height of the measured vehicle and the second parameter is selected to control the air restriction valve such that air losses of the air suspension control system are minimized.

In another advantageous embodiment, a method of increasing the running stability of a vehicle is provided, which comprises selecting a vehicle height value, measuring an actual vehicle height value, and selecting a vehicle height value selected to generate a correction signal. Comparing the measured vehicle height value. The method includes operating a height control valve in accordance with a correction signal to maintain a selected vehicle height value, generating a control signal different from the correction signal, corresponding to the operation of the onboard vehicle system, and improving driving stability of the vehicle. Selectively operating the limiting valve as a control signal to selectively stop the operation of the height control.

In another advantageous embodiment, a method of minimizing air loss in a vehicle air suspension system is provided, which couples an inlet port of a height control valve to a pressurized air source, which couples an exhaust port of the height control valve to the atmosphere. Coupling the air spring port of the height control valve to the air restriction valve, and coupling the air restriction valve to the air spring. The method includes measuring a first parameter, generating a first control input based on the first parameter to control the height control valve, and receiving a second control input based on the second parameter to control the air restriction valve. Generating the second parameter is different from the first parameter. The method also includes applying a second control input to the air restriction valve to prevent loss of pressurized air in the air suspension control system during operation of the vehicle, and selectively operating the air restriction valve in accordance with the second control input. It further comprises the step of.

In another advantageous embodiment, a vehicle air suspension control system is provided having a height control valve having an air inlet port connected to a pressurized air source, an exhaust port connected to the atmosphere, and an air spring port connected to an air spring. The height control valve can be operated to selectively engage between the air inlet port and the air spring port, between the exhaust port and the air spring port, or between the air inlet port, the air spring port, and a neutral position where the exhaust ports are isolated from each other. have. The height control valve is controlled by a correction signal corresponding to the vehicle height measured by the first vehicle system parameter. The system further includes an air restriction valve coupled between the height control valve and the air spring, which selectively restricts the flow of pressurized air between the height control valve and the air spring to minimize air loss in the air suspension control system. Can be operated to. The system also has a control signal for controlling the air restriction valve, the control signal corresponding to a second vehicle system parameter that is different from the first vehicle system parameter. The system is further provided such that the first vehicle system parameter corresponds to the measured vehicle height.

The invention and its specific features and advantages will become more apparent from the following detailed description considered with reference to the accompanying drawings.

1 is a block diagram of an advantageous embodiment of the present invention.

1A is a block diagram illustrating another advantageous embodiment of the present invention.

1B is a block diagram illustrating another advantageous embodiment of the present invention.

2 is a block diagram according to FIG. 1 showing the control input in more detail.

3 is a block diagram illustrating another advantageous embodiment of the invention.

4 is a flow diagram illustrating a sequence of operations for one advantageous embodiment of the present invention.

5 is a block diagram illustrating another advantageous embodiment of the present invention.

6 is a diagram of the piping according to FIG. 5, showing an advantageous embodiment of the invention.

Referring to the figures and, in particular, FIG. 1, one advantageous embodiment of the air suspension system 10 is shown as a block diagram. The air suspension system 10 is provided with a pressurized air source 12 fluidly coupled to the height control valve 14.

The height control valve 14 is operated in a conventional manner, which has an air inlet port 11, an air spring port 13, an exhaust port 15, and a central hole or cavity (not shown), the center The ports are selectively in fluid communication with one another through holes or cavities in the chamber. The air inlet port 11 is provided to receive pressurized air from the pressurized air source 12. In addition, an air spring port 13 is provided to fluidly couple the height control valve 14 to the air spring 18. Moreover, the exhaust port 15 is provided to fluidly couple the height control valve 14 to the atmosphere.

Although the operation of the height control valve 14 is typical, it will be described here for clarity. The height control valve 14 receives a transducer input (not shown), which corresponds to a measurement of the distance between the traction arm (not shown) and the vehicle frame (not shown). The measured value is compared with the selected reference value to determine whether it is greater than, less than or equal to the selected reference value. If the measured value is greater than the selected reference value, the height control valve will open the fluid communication between the air spring port 13 and the exhaust port 15 to evacuate air from the air spring 18 and thereby tow The distance between the arm (not shown) and the vehicle frame (not shown) is reduced. Alternatively, if the measured value is less than the selected reference value, the height control valve opens fluid communication between the air spring port 13 and the air inlet port 11 to introduce additional pressurized air into the air spring 18. Thereby increasing the distance between the towing arm (not shown) and the vehicle frame (not shown). Finally, if the measured value is equal to the selected reference value or range of reference values, the height control valve 14 will keep the ports in fluid isolation from each other.

However, when the vehicle is in normal operation, problems arise, for example, vibrations occur from side to side, front to back, or a combination thereof in the movement of the vehicle. The height control valve accepts a continuously varying measurement of the distance between the traction arm (not shown) and the vehicle frame (not shown), so that the system adds air to the air spring 18 in response to the measured value or The cyclic movement to evacuate therefrom is continuously performed.

For this problem, an air limiting valve 16 is provided and positioned between the height control valve 14 and the air spring 18. An air restriction valve 16 is provided such that fluid communication is limited between the height control valve 14 and the air spring 18 when the air restriction valve 16 is actuated. The air restriction valve 16 may have any suitable valve assembly for use with vehicles, which selectively facilitates or restricts fluid communication between the height control valve 14 and the air spring 18. It is appropriate. It should also be noted that the air restriction valve 14 has a valve assembly which partially restricts the fluid coupling between the height control valve 14 and the air spring 18, or otherwise completely makes the fluid coupling. It can be provided.

By reducing or even eliminating the periodic movement of the air suspension system, the management of running height will be greatly improved. Air suspension systems are cycled less frequently, which results in less wear in the system and reduces the costs associated with running the system. This is because adding and evacuating compressed air to the air springs in response to the vibration of the vehicle itself causes the vehicle to swing and shake in a periodic manner. This is not very hopeful as it tends to impair the stability of the run and is very important for large profile vehicles. The system will not destabilize the vehicle as in many other systems that perform periodic movements during normal operation of the vehicle.

Although the air restriction valve 16 is shown in one embodiment of FIG. 1 as being separate from the height control valve 14 and the air spring 18, this is not required. For example, air restriction valve 16 may be piped into the air line and physically separated from both air spring 18 and height control valve 14 shown in FIG. Alternatively, the air restriction valve 16 may be integrally formed into the height control valve 14 as shown in FIG. 1A, or the air limiting valve 16 may be the air spring 18 as shown in FIG. 1B. It can be further formed integrally into). It should be taken into account that the physical position of the air restriction valve 16 may vary depending on the design of the vehicle.

The air limit valve 16 is further provided with a control input 20. The control input 20 will selectively activate the air limit valve 16 in accordance with the selected control logic. During normal operation of the vehicle, it is desired that the air limiting valve 16 restrict fluid communication between the height control valve 14 and the air spring 18 to minimize the loss of air due to, for example, vibration of the vehicle. That's right. For example, when loading or unloading a vehicle causing a large change in the weight or movement of the cargo, when the vehicle approaches the loading dock and the height of the trailer must be adjusted to match the loading dock height, It is generally desired that the height control system be activated when the tow truck is to be connected to or released from the trailer, or when adjustment of the air springs is necessary, for example when a heavy weight change occurs to level the trailer.

2 is a block diagram according to FIG. 1 showing the control input 20 in more detail. Although multiple inputs are shown in FIG. 2, control input 20 may include any number of inputs, for example, from, but not limited to, onboard vehicle data sensing and control system.

The control input 20 may comprise, for example, but not limited to, a braking system signal 21, which may be, for example, an anti-lock braking system (ABS). , Traction Control System (ASR), or Integrated Coupling Force Control (CFC). The control input 20 may also have a time measurement signal 22, which may include elapsed time measured from a specified event or system activation, for example. The control input 20 may further comprise an operator input signal 23, which may be a manually input signal for overriding the system or programmed into the system by the operator. It can be an automatic signal. The control input 20 may further comprise a height measurement signal 24, which may for example be the height of the vehicle frame, the towing arm or any other part of the vehicle. The control input 20 may also further include motion sensor (s) signal (s) 25, which may be located on the tractor or trailer to measure the motion of the vehicle. The control input 20 may include any number of vehicle data and / or control signals and does not mean that the particular signals listed herein are a comprehensive list, but merely various vehicle and operator systems. It should be considered that this is an example of the various signals that can be derived from them. It should also be noted that the control input 20 may comprise any, or any combination of the vehicle's data and / or control signals desired for a particular application.

The various system signals listed in relation to the control input 20 were selected because of the impact that the vehicle system may have on driving stability. For example, in the context of braking systems, ABS prevents the wheels of the vehicle from locking while braking. Sudden changes in vehicle speed cause dramatic changes in vehicle load, which may require the air suspension system 10 to adjust the air spring 18 to rebalance the trailer. In contrast, ASR is used to ensure that none of the wheels on the driven axle rotate during acceleration, thereby ensuring optimal traction with the road surface. This is a situation where there may be a dramatic change in vehicle load, requiring the air suspension system 10 to adjust the air spring 18 to compensate for the change in load. As another alternative, the braking system signal 21 can be generated by an Electronic Braking System (ESB) incorporating ABS and ASR functions into a single system over signal. In addition, an integrated Coupling Force Control (CFC), which adjusts the distribution of braking force and coordinates braking between the tow truck and the trailer, can be used in connection with the control input 20.

Various other signals listed in connection with the control input 20 can impact driving stability. For example, if the distance between the towing arm and the vehicle frame is changed beyond the threshold value by changing the vehicle load, the air suspension system 10 may adjust the air spring 10 to re-level the trailer. The height measurement signal 24 can be used. In another example, the motion sensor signal 25 may cause the motion sensor signal 25 of the vehicle to be limited such that fluid coupling between the height control valve 14 and the air spring 18 is limited during normal operation of the vehicle to minimize air loss and stop the periodic motion of the equipment. It can be used to sense movement. An operator input signal 23 can also be used in conjunction with the control input 20, for example, such that the height control valve 14 can continuously operate the air spring 18 during normal vehicle operation. The operator of may want to temporarily disconnect the air restriction valve 16, or the operator of the vehicle may want to disconnect the air suspension system for a period of time.

Referring to FIG. 3, another embodiment of an air suspension system 10 is shown in block diagram form. In this embodiment, the air suspension system 10 has a pressurized air source 32 fluidly coupled to the inlet port 31 of the height control valve 34 and the inlet port 37 of the height control valve 36. . Furthermore, the height control valves 34, 36 have exhaust ports 35, 41, respectively, which are each fluidly coupled to the atmosphere. The height control valves 34, 36 further have inlet ports 33, 39, which fluidly couple the height control valves 34, 36 to the air restriction valves 38, 40, respectively. Both height control valves 34 and 36 have a central hole or cavity (not shown), through which ports are selectively in fluid communication with one another.

Air restriction valves 38 and 40 are fluidly coupled to air springs 42 and 44, respectively. Air limit valves 38 and 40 are similar to those previously described with reference to FIG. 1 and will not be described again herein.

Control inputs 46 are provided on both air restriction valves 38, 40. The operation of the control input 46 and the height control valves 34 and 36 is similar to that described with reference to FIG. 1 and therefore the description will not be repeated here.

Shown in FIG. 3 is an air restriction 46. The air limiter 46 connects the air spring 42 through the air spring 44 and the air limiter. The purpose of the air restriction 46 is to equalize the pressure in the air springs 42 and 44. However, the air limiter 46 restricts air flow from one air spring to the other such that rapid equalization of the air spring through the air limiter 46 is not possible. Rather, if a deviation of pressure exists between the air spring 42 and the air spring 44, the air limiter 46 is only a small amount at a time so that the air limiter 46 allows equalization over a period of time. Allow air to pass. Of course, the duration of time will vary depending on the pressure deviation.

While two height control valves, two air limiting valves, and two air springs are shown in FIG. 3, they can be used in any number depending on the configuration of the vehicle and the control design of the desired vehicle. Should be considered. Moreover, the air restriction valves 38, 40, shown separated and separated from the height control valves 34, 36 and the air springs 42, 44, were previously described with reference to FIGS. 1A and 1B. As such, it may be manufactured integrally with the height control valves 34, 36 or the air springs 42, 44.

4 is a flow chart showing an operational sequence for a method of minimizing air loss in an air suspension control system. For simplicity, the flowchart of FIG. 4 will be described with respect to the air suspension system 10 shown in FIG. 1.

Initially, the operator will select the vehicle suspension height 50. This corresponds to the desired height between the towing arm and the vehicle frame. Alternatively, such height may be automatically selected depending on the manufacturer's settings or onboard vehicle control system, or such height may be manually selected. Once this height is selected, the system will measure the vehicle height 60. In many systems, the height control valve 14 is mounted to the vehicle frame and provided with a control arm connected to the towing arm via a coupling device. The connecting device causes the control arm to rotate the control shaft inside the height control valve 14 when the distance between the traction arm and the vehicle frame changes. This in turn controls the introduction of air into or out of the air spring 18. Although mechanical linkages are widely used and currently used to measure the distance of change between the axle and the vehicle frame, include optical sensors, variable capacitors, variable resistors or any other transducer suitable for use with the vehicle. Other measurement transducers can be used effectively, but are not limited to such.

Once the measured value of the vehicle height is obtained, the system determines whether the vehicle height matches the selected height 70. This is accomplished by simply comparing the measured vehicle's height with a value of the selected height or a range of values, to produce one of positive, negative or no deviations. If the measured vehicle height is adjusted to the selected vehicle height so that there are no deviations, the system loops back to measure the vehicle height 60 and repeats this period until the interrupted or measured value does not match the selected value. Will continue.

However, if the measured vehicle height did not match the selected vehicle height with a positive or negative deviation, the system proceeds to determine whether the control input has deactivated the height control 80. For example, the height control system can be deactivated when the control input 20 activates the air restriction valve 16 to limit fluid engagement between the height control valve 14 and the air spring 18. If it is determined that the air limit valve 16 has been activated, the system is fed back to measure the height 60 of the vehicle and may continue this cycle until it is stopped or until the system measures that the air limit valve 16 has been activated. will be. However, if the air restriction valve 16 has not been activated, the system proceeds to adjust the air spring in accordance with the measured height 90 to add compressed air to or evacuate the compressed air therefrom.

As previously described with reference to FIG. 2, any number of variable vehicle data and control signals may be used for the control input 20 to control the limit valve 16. The logic sequence selected to control the limiting valve 16 will vary according to the selected signals, the number of which is described in FIG. Although a number of various control inputs have been shown and described in connection with the control input 20 as previously described, any number of various onboard vehicle data system inputs may be used to control the air restriction valve 16. have. Further consideration should be given to the interpretation of control signals and / or onboard data corresponding to the control inputs, that the particular order is not critical.

In addition, the control logic for the height control valve 14 and the corresponding adjustment of the air spring 18 have already been described with reference to FIG. 1 and will not be repeated here.

5 is a block diagram of another advantageous embodiment of the present invention. Shown is the air suspension system 100. The air suspension system 100 has a pressurized air source 110 in fluid communication with the height control valve 112 via an air inlet port 111. The air suspension system 100 further includes an air restriction valve 114 in fluid communication with the height control valve 112 via an air spring port 113. The height control valve 112 is provided with an exhaust port 115 that can be in selective fluid communication with the air spring port 113. The air spring port 113 may be in more fluid communication with the air inlet port 111 based on the selected logic.

The air limit valve 114 is provided with a control input 120, which may have various onboard data and control signals as previously described with reference to FIG. 2.

Air spring 116 and air spring 118 are shown in fluid communication with air restriction valve 114 such that both are regulated simultaneously. This configuration has the advantage that the number of parts is small and therefore low in terms of installation and operation.

FIG. 6 is a piping diagram of the air suspension system 100 according to FIG. 5. As shown in FIG. 6, the piping diagram includes: an air inlet 120 for the pressurized air source 110 connected to the height control valve 112, and the height control valve 112 includes an air restriction valve ( 114) again; And the air restriction valve 114 is connected to both the air spring 116 and the air spring 118.

Although the air restriction valve 114 is shown as separate from the height control valve 112 in FIGS. 5 and 6, it is possible that the height control valve 112 can be provided integrally as shown in FIG. 1A. It should be noted.

Although the present invention has been described with reference to specific arrangements of parts, features, and the like, they are not intended to represent all possible arrangements or features, and many other variations and modifications will be apparent to those skilled in the art. will be.

The present invention can be applied to a suspension system in a vehicle or the like.

Claims (18)

Pressurized air source; Air springs; A height control valve having an air inlet port connected to the pressurized air source, an exhaust port connected to the atmosphere, and an air spring port connected to the air spring, the air inlet port and the air spring port, the exhaust port and the air spring port, or the air A height control valve operable to selectively engage an inlet port, an air spring port, and a neutral position where the exhaust port is isolated from each other; An air restriction valve fluidly coupled between the height control valve and the air spring and operable to selectively open and close communication between the height control valve and the air spring; A first control input for controlling the height control valve, the first control input based on a first parameter; A second control input for controlling the air restriction valve, the second control input being based on a second parameter different from the first parameter,  To minimize air loss in an air suspension control system, the first parameter includes a measured vehicle height and the second parameter is selected to control the air restriction valve. The method of claim 1, The second parameter is selected from the group consisting of: anti-lock braking system, traction control, electronic braking system, motion sensors, operator input, time measurement or combinations thereof. , Air suspension control system for vehicles. The method of claim 1, The second control input is selected from the group consisting of: electrical signal, pneumatic signal, mechanical signal or combinations thereof. The method of claim 1, And the second control input automatically activates the air restriction valve based on the selected control logic. The method of claim 1, The air restriction valve is separate from the height control valve. The method of claim 1, The air restriction valve is integrally formed with the height control valve. The method of claim 1, And the air restriction valve is integrally formed with the air spring. Selecting a value of the vehicle height; Measuring a value of the actual vehicle height; Comparing the value of the vehicle height selected to generate a correction signal to the value of the measured vehicle height; Operating the height control valve in accordance with a correction signal to maintain a value of the selected vehicle height; Generating a control signal different from the correction signal, corresponding to activation of the onboard vehicle system; Selectively operating the limiting valve as a control signal to selectively stop the operation of the height control to increase the running stability of the vehicle. The method of claim 8, An onboard vehicle system is a group consisting of an anti-lock braking system, traction control, electronic braking system, motion sensor, operator input, time measurement, or a combination thereof. And from the method of improving driving stability of the vehicle. The method of claim 8, The control signal is selected from the group consisting of electrical signals, pneumatic signals, mechanical signals or combinations thereof. Coupling the air inlet port of the height control valve to the pressurized air source; Coupling the exhaust port of the height control valve to the atmosphere; Coupling an air spring port of the height control valve to the air restriction valve; Coupling the air restriction valve to the air spring; Measuring a first parameter; Generating a first control input based on the first parameter to control the height control valve; Generating a second control input based on a second parameter different from the first parameter to control an air restriction valve; Applying a second control input to the air restriction valve; And, Selectively actuating the air restriction valve in accordance with the second control input to prevent loss of pressurized air in the air suspension control system during operation of the vehicle; minimizing air loss in the suspension control system for the vehicle. Way. The method of claim 11, The second parameter is: minimizing air loss in a suspension control system for a vehicle, which is selected from the group consisting of anti-lock braking system, traction control, electronic braking system, motion sensors, operator input, time measurement or combinations thereof. How to let. The method of claim 1, The second control input is selected from the group consisting of an electrical signal, pneumatic signal, mechanical signal or combinations thereof, the method of minimizing air loss in a suspension control system for a vehicle. A height control valve having an air inlet port connected to a pressurized air source, an exhaust port connected to the atmosphere, and an air spring port connected to the air spring, wherein the air inlet port and the air spring port, the exhaust port and the air spring port, or the air inlet port A height control valve operable to selectively engage an air spring port and a neutral position where the exhaust port is isolated from each other, the height control valve being controlled by a correction signal corresponding to the vehicle height measured by the first vehicle system parameter; An air restriction valve coupled between the height control valve and the air spring and operable to selectively restrict the flow of pressurized air between the height control valve and the air spring to minimize air loss in the air suspension control system; A control signal for controlling the air restriction valve, the control signal corresponding to a second vehicle system parameter different from the first vehicle system parameter, The first vehicle system parameter corresponds to the measured vehicle height. The method of claim 14, The second vehicle system parameter is selected from the group consisting of: anti-lock braking system, traction control, electronic braking system, motion sensors, operator input, time measurement or a combination thereof. The method of claim 14, And the control signal is selected from the group consisting of electrical signals, pneumatic signals, mechanical signals or combinations thereof. The method of claim 14, The control signal automatically actuates the air restriction valve based on the selected control logic. Fluid source; Fluid springs; A control valve having an inlet port for receiving fluid from a fluid source, an outlet port for discharging fluid from the fluid spring, and a fluid spring port connected to the fluid spring, the control valve comprising: Or a control valve operable to selectively engage between an inlet port, a fluid spring port, and a neutral position where the exhaust port is isolated from each other; A restriction valve fluidly coupled to the control valve and operable to selectively open and close fluid communication from the fluid source to the fluid spring; A first control input for controlling said control valve, said first control input comprising a measured vehicle height; And, And a second control input for controlling said limiting valve, said second control input being selected to control said limiting valve so that the periodic movement of a control system is minimized.

Images